Lighting designers pay a great deal of attention to the quality of the lighting provided, expressed in horizontal foot-candles. Too often they fail to bear in mind the fact that the objects of primary attention are viewed from the side and, consequently, are seen primarily or only in a vertical plane. For example, in a sports arena, a moving ball, or players, may be seen from the side, primarily. Therefore, the light levels in a generally vertical plane are very important, but are generally inadequately lighted.
Despite the above being fairly obvious, it is most common today to mount the High Intensity Discharge Bulbs (HID(s)) so that the vast majority of the light descends to the floor, and a relatively small amount of the light strikes the vertical surfaces such as are commonly found in warehouses, sports arenas, supermarkets, etc. I have designed a new reflector which produces a higher ratio of vertical to horizontal illuminance, and which yields improved overall visibility in situations where vertical surfaces are of substantial importance. As a result both lighting performance and increased safety are provided, and the lighting is free from shadows and hot spots. The lighting equipment available heretofore has been inefficient and non-cost-effective. In addition, it has been non-uniform.
Conventional high intensity discharge (HID) installations at industrial locations require great wattage. Consequently, fluorescent lighting for expansive areas has been adopted widely because of its marked efficiency, as compared to incandescent lighting. The use of such lighting, however, has been plagued with the early burning-out of the fluorescent bulbs, particularly when they are first energized. Such installations are commonly energized through an electronic-only ballast, and that combination has proved to be very economical, except for the heavy burn-out losses of the lamps. Thus, a need exists for some way of substantially reducing the early burning-out of such lamp installations.
The primary feature of my invention is the interior reflective surface of the inverted U-shaped channel member which is characterized by the use of a series of elongated flat reflective panels extending lengthwise of the channel member in parallel side by side relation, and at a prescribed angle thereto. These panels have a reflective inner surface, facing downwardly and outwardly, and extend at an angle of about 22-32xc2x0 relative to each other. They function to spread the light which they reflect downwardly so as to overlap each other""s reflections markedly, and thereby diffuse the light and spread it to make it more uniform and avoid the formation of shadows and hot spots, while improving the visibility and producing a higher ratio of vertical to horizontal illuminance.
After years of experimenting, I have discovered a way of substantially reducing the number of burned-out fluorescent lamps while accomplishing a substantial saving and increasing the quantity of light. I have found that if the wattage which is passed through the fluorescent lamp is substantially reduced, the burning-out rate is also substantially reduced. I believe this improvement occurs if the lamp filament is subjected to a lesser current initially, as upon lighting. In the current use of fluorescent lamps, it has been conventional to utilize an electronic-only ballast, which does not provide the cushioning of the filament which I believe may be required, if the rate of burning-out is to be reduced. I have discovered that if a hybrid magnetic-electronic ballast is utilized to power the bulbs, the wattage required to energize a 55 watt fluorescent bulb can be reduced from the conventional approximately 300 watts, to 206 watts, which constitutes a substantial savings. In addition, the rate of burn-outs of the fluorescent lamps is substantially reduced, and the resultant lighting is increased about three (3) foot-candles. I find that I can increase the efficiency of the lighting system by 10% and improve its cost-effectiveness by 35%-70%.
I believe some of the improved performance described above is accomplished by the use of a transformer within the ballast, in combination with the conventional features of a purely electronic ballast, the latter of which is what is commonly utilized in fluorescent industrial lighting installations. I believe that the transformer, by being inserted into the prior conventional circuit leading into the 55 watt fluorescent bulb, has a stabilizing effect upon the current which is delivered to the fluorescent bulb filament, I believe that this stabilizing effect is provided as a result of the transformer removing substantial fluctuations in the current, and that it has been these fluctuations which have caused the filaments of such fluorescent bulbs to burn-out prematurely.
Thus, it is an object of my invention to provide a light reflector of improved construction to effect a substantial improvement in quality of light reflected thereby.
It is another object of my invention to furnish an improved light reflector which is designed to provide lumen saturation so as to eliminate shadows and hot spots.
Another object is to furnish a light reflector configuration and placement which provides increased foot-candle readings at any single point in the work plane into which its reflected light is directed.
Another object of my invention is to provide a light reflector configured and positioned to produce a more uniform light distribution.
Another object is to provide a lighting installation which will operate at a substantial savings, in that it burns substantially less wattage.
Another object is to furnish a light reflector configured and positioned to provide a great lumen overlap, resulting in excellent foot-candle ratings and improved uniformity in light distribution.
These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which: